1. Statement of the Technical Field
The inventive concepts relate to unmanned vehicles, such as unmanned ground vehicles (“UGVs”), configured to operate in response to commands from a remotely-located control unit.
2. Description of Related Art
Unmanned vehicles are motorized vehicles that operate without an on-board human presence. Remotely-controlled and remotely-guided unmanned vehicles, such as UGVs, are in widespread use in applications such as explosive ordinance disposal (“EOD”), search and rescue operations, hazardous material disposal, surveillance, etc. A typical UGV can include, for example, a frame or chassis, wheels and drive motors mounted on the chassis, an articulating arm mounted on top of the chassis, and grippers and a camera mounted on the arm. UGVs can be equipped with steerable front wheels to facilitate directional control. Alternatively, UGVs can include tracks that facilitate operation over rough terrain. Steering of tracked UGVs can be effectuated, for example, by simultaneously operating the wheels on opposite sides of the UGV in opposite directions.
Movement and steering of a UGV, and operation of its robotic arm, grippers, camera, and other accessories can be controlled by a user from a location remote from the UGV, using a joystick-equipped control unit that communicates with the UGV by way of a wireless communication link. Movement of the UGV is typically controlled by modulating the velocity of UGV in proportion to the displacement of the joystick or other input device of the control unit.
UGVs are often used indoors, in low-light and other limited-visibility conditions, and in small areas with limited maneuvering room. Also, a UGV may need to be maneuvered near and around obstacles and hazards such as live ordinance or radioactive material. In many applications, velocity control may not be able to provide the relatively high degree maneuverability necessitated by these operational requirements. For example, it can be difficult to precisely modulate the speed of a UGV, and its resulting position change, using a joystick controller, due to the relatively short range of travel of a typical joystick. Moreover, it can be difficult for a user to recognize and then command the precise velocity needed to position the UGV in a desired position. Thus, a user typically needs to “creep-up” on the final desired position of the UGV by repeatedly jogging the joystick or other input device as the UGV approaches the desired position, to facilitate the final movement of the UGV in small, discrete increments. Moreover, the imprecision associated with velocity control can increase the potential for the UGV to overshoot the desired position and collide with the object being examined or manipulated.